Hi, thanks for writing to HCM.
A pulled muscle will not present with pain for so much length of time (>5 weeks) despite treatment. So it is unlikely in your case.
Presence of pain, limitation of movement in the knee joint even 5 weeks after injury
I suspect either injury to the ligaments or meniscus
in the knee joint. I suggest you to undergo MRI scan of the knee joint to ruleout these conditions.
Consult an orthopedic surgeon and follow his advice.
Hope this information is helpful. Good day